Lift truck



" April 21,1942.y W. STUEBING, JR 2,280,104

LIFT TRUCK 3 Sheets-Sheet 2 Filed Dec. 14, `1940 April 21, 194.2.`

' W.` STUEBING, JR

` LIFT TRUCK 3 Sheets-Sheet 5 Filed Dec. 14, v 1940 INVENTOR .Piane-ed apr. 21, 1942 a urr 'raven Walen Stneiikng, Jr., Cincinnati, ()himassig'nor Incorporated, Cincinnati, Ohio,

aoorporationof Ohio Anuncian December 14, 1940, seal No. 370,090

' l2 Claims.

This invention relates to lift trucks and more particularly to hand operated lift' trucks where the lifting operation is performed by swinging the steering handle. i

An object of this invention' is to provide a manually operated mechanism which may be used, for example, for lifting movable platforms of theI type where a quantity of material is piled on the platformand the platform is then moved. A further object is. to provide an eiiicient and dependable means for lifting a load and for movi ing the load.

vide a mechanism of the above character which is sturdy in construction and emcient in operation, and which is light in weight and'economical to manufacture.v A further object is. to pro vide a mechanism which may be used with perfect safety under awide variety of conditions. Other objects will be in part obvious and in part pointed out hereinafter.

' tures of construction, combination of elements, and arrangements of parts as will be exemplified in thestructure to be hereinafter described'andv thel scope of the application of which will be indicated in the following claims.

In the drawings in which one exnbodirnentof` Figure 2 is a sectional view on the line 2-'2 of Figure 4:'

l Figure 3 is similar to Figure 2 but shows cer- 4 tain parts of the apparatus at a different stage Y in the cycle of operations:

Figure 4 is a top plan view of the forward end of the truck with certain partsbroken away for clarity; and, l

Figure E` is a perspective view of the mechanism shown in Figure 4. .l

This applicationis related to my application, Serial No. 317,069, led February 3, 1940, entitled Lift truck and issued December 10, 1940, as Patent No. 2,224,166', and material shown here and not covered ,in this patent is covered in the present application.

In' the illustrative embodiment of theinvention, thelift truck is completely manual and'it is used' to lift loads and move the loads from one plaeeto anothen- A lower frame or chassis is provided with wheels, and this chassis carries a lifting frame which may-be moved to and from a raised position, in which position it supports the load; The truck is provided at its, forward A still further object is to' pro- `The invention accordingly consists in the feal end with a steering handle and it may be backed beneath a load such as a movable platform upon which is piled the materlalto bellfted and moved. With the lifting frame beneath 'the platform, the

`5 lifting frame is raised Vby swinging the steering handle with the result that the load is lifted and fully supported by the lift truck. The lift truck is then moved and the load is carried to the new location whereupon the lifting frame is lowered, releasing the load.

In the present embodiment the liftingframe is raised by means .of a hydraulic ram which is operated by swinging the steering handle there Ybeing a releasable mechanical connection beram. 'I'he vhydraulic ram is of such a character that it acts as an automatic latching means to hold the ,liftingframe in partially or fully elevated position, and it also acts as a checkto retard the descent of the lifting frame. This embodiment is also provided with safety means which prevents the operator from elevating the ^lifting frame beyond a certain predetermined limit.

Furthermore, when a load is elevated and the operator wishes to release it, it is desirable that he befree to-attend to the truck and to guide the load as it settles. Accordingly, with the present embodiment, the load is automatically latched in partially or fullyv raised position, and when the release treadle is actuated the hydraulic ram is rendered ineffective except as a check until the l lifting frame and the load have fully returned u from`the elevated position. Thus,the operator 3:, need only actuate the treadlei and heis then free to give his attention to thecontrol and the truck.

Referring particularly to lFigure 1 of the'drawings, a lower frame 2 is provided with a pair of 40 rear wheels 4 mountedI upon an axle 6 .and at the right with a pair of front wheels 8 mounted upon an axle In. LAxle l0 is mounted in a fork i2, rigidlysecured to the lower end of a king bolt i4. King bolt i4 extends through a crosshead i6 which forms the forward fend of theV lower frame 2. The lower frame 2 is provided at the rear with reinforcing brace Astructure I1 iwhich carries a shaft 32, and at the forward end with a frame construction, generally indicated at 2i, Whichacts as a reinforcing means and which `also supports the mechanism for elevating the lifting frame 22. The lifting frame 22 is Af ormed by a U-shaped side member 2l extending along the sides and the rear of the truck, a rear brace structure 2| and a saddle-like front tweenthe steering handle and the hydraulic of the load 4suiliciently to release the load.

which areto the left and downwardly. Thus, the lifting axle is subjected to directly opposed forces with the forces on the ends of the axle tending to balance the force on Ithe center of -the axle. Axle |02 is sufliciently sturdy to remain rigid when subjected to these forces, and thus the vforces tend to counterbalance each other through the axle, and tothe extent that they do counterbalance each other, the forces are not transmitted tothe frame.

With the steering handle raised as in Figure 1, if it is desirable Ato disengage the steering handle vfrom the linkage mechanism, the steering handle is lifted upwardly through` steering-handle sleeve 48, and the handle is thenswung down with the extreme end of the latching portion 12 riding upon the surface 55 of the disc segment 54. Thus, the steeringhandle is held in this extended position and may be used as a handle to pull, push and otherwise manipulate the truck. If the steering handle is pulled outward- 54, the operator may at any time raise the han-fy matically when once it is started, and in the present embodiment this is accomplished by p'rodle to the vertical position, and the-handle automati'cally drops to the position` shown in Figure l,

' with latch 12 falling behind the rear of the segment. Thus, the handle is held from falling and may be used to elevate the lifting frame y.when

desirable. The front cross-frame 28 acts as a load bumper and limits the movement of the truck under `a load. The truck is therefore backed under the load as far as it will go, and the load is then raised by-a pumping movement on the steering handle 40. l Y

As indicated above, the hydraulic ram |24 acts as an automatic latching mechanism to hold the load at the end of eachdstroke, and it continues to actin this capacity while the truck is being wheeled about to thereby move the load to its new location. When the load is elevated, it may be released by stepping on a foot treadle 15 which is rockably mounted by meansof a pivot 18 on head I6. `Referring to Figure 5, treadle 15 is connected through an adjustable release rod |32 to the upper end of a release lever |84 which is.

pvotedat its lower end A(see. Figure 2)` on a pivot |35, carried bythe frame construction 2|.. Release lever |34 is provided with an outwardly ex- `tending flange |35 which hasan arcuate portion |38 connected to the load releasing; rod |30. Ac-

" cordingly, load releasing rod 30 is provided with a T-extension |40, the `cross-member of which y engages the right-hand surface of the 'arcuate portion |58, and the longitudinal portion ofwhich extends through a hole in the arcuate portion |38 and is adjustably attached to the load releasing rod. As pointed` out above, the load -ree5 leasing rod is held inwardly by a spring, and when l the rod is pulled to the right, a valve is opened which releases the load. The spring acting on Ithe load releasing rod normally holds foot treadle 15 in the position shown in Figure 2, and when thefoot treadle is depressed, as shown in Figure 3, the load releasing rod -is pulled outwardly As has been indicated, it is desirable that the `load releasing operation be l carried on autoviding a releasable latch for holding treadle 15 in its depressed position (Figure 3). Accordingly,

a treadle-locking arm |42 (see also Figure 5) is mounted to rock freely upon the extended end of lifting axle |02, and the end of the treadle-locking arm is provided with alatch portion |44 which is adapted to engage` the latch pin |46` rigidly carried by treadle 15. When the treadle is in its raised position, the treadle-locking arm is held upwardly as shown in Figures 5 and 2, but when the treadle is depressedv (as shown in Figure 3) the treadle-locking arm falls, and its latching portion 44 interengages w'ith the latch pin |40 and holds the treadle depressed. Thus, the operator may remove his foot and the load continues to descend.

The treadle-locking arm |42 is provided with a side bracket` |48 which carries an adjustable n set screw |55, and lifting arm |04 is provided with a heel portion |52. When the lifting frame 'is moving downwardly, heel portion |52 swings toward the position shown in Figure 1, and set screw |50 is so adjusted that its lower end is engaged by the heel portion when the lifting frame has returned from the elevated position. Due to this engagement, heel portion |52 pushes treadlelocking arm |42 upwardly out of engagement 'with latch pin |45, and treadle 15 is released, and

the spring acting o n loadreleasing rod |30 returns the elements to the position of Figure l. Thus, when the 'treadle is pushed down, the lift'- ing frame automatically returns to the position of Figure 1, and the return of the lifting frame automatically releases the treadle and closes the valve of releasing rod |30 so that the mechanism is conditioned for further use in lifting a load. The adjustments of set screw |50 and load releasing rod |32 are held by suitable lock nuts.

Itis important that safety means be provided to prevent the elevation of the liftingframe beyond a desirable limit. This is particularly im-r portant in the present embodiment where the lifting isaccomplished by operating a hydraulic ram as this type of mechanism gives to the operator tremendous power in moving the lifting frame. Thus, if `mechanical stops were provided to limit the elevation of the lifting frame, the mechanism might be damaged or broken without the operator realizing that he has reached the limit of movement of the lifting frame. In the present embodiment, this diflculty is avoided by providingmeans to open momentarily the release valve whenever the lifting frame reaches the maximum' elevation which is desirable. Accordingly, lifting arm |04 is provided with an integral lug |54 which is adapted to engage the sleeve |56 (see also` Figure v4) of release lever |34 when thelifting arm swings beyond a certain limit. Insofar asthe elevating of the lifting frame is accomplished by swinging the lifting arms |04 and |06, lug |54 engages sleeve |56 of'the release lever at any time that the lifting frame is movedbeyond a. certain predetermined desirable limit. Thisengagement swings the release lever "|34 and pulls releasing rod |30 (see `Figure 2) to the right suflclently to open the releasing valve,

and the hydraulic ram therefore ceases to hold the lifting frame until the releasing valve is permitted to reclose. Thus, when the lifting frame is raised during a particular pumping stroke to the point where the releasing valve is opened, the lifting frame is not held in this position but immediately begins to drop. This` dropping-or definitely without danger of injury to the mechai nism, as the lifting frame will always return at the end of a stroke the same distance it was raised during that stroke. During this time, the movement of releasing lever |34 causes treadle 15 to swing downwardly, but this movement lis not` sufficient to permit treadle-locking 'arm |42 to fall, and the load is not dropped below the position where lug |54 disengages sleeve |56.

As many possible embodiments may be made of the above ,invention and as many changes might be made in the embodiment above set forth, it is Q to be understood that all matter hereinbefore set forth, or shown in the accompanying drawings, is to be interpretedas illustrative and not in a limiting sense. Y

I claim: l

combination of: a chassis comprising a supporting frame having mounted thereon a set of wheels vsteering handle is swung from its vertical position toward-its` horizontal position, said operating means including means to hold said lifting frame` inraised position;'releasing means to release the lifting frame when elevated compris- I, l. In lift truck apparatus of the classv described, the combination of: a base frame; a lifting frame mounted vupon said vbase frame to be moved upwardly to thereby lift the load; operating means to manually raise said lifting frame and to hold said lifting frame in its raised position; releasing means to render said operating means ineffective and operable when said lifting frame is raised to'thereby permitthe return of said lifting frame to its lower position; and means operated by the movement ofv said lifting frame and effective when said lifting frame reaches its lower position to render said releasing means ineffective. A v

2. In apparatus of the character described, the

combination of: a chassis comprising asupporting frame having mounted thereon a set of wheels yand a' steering handle; a lifting frame mounted upon said chassis and adapted to be moved to and from a raisedposition where it engages and lifts a load; means to elevate said lifting frame comprising, a hydraulic pump which is autoand means to hold said' releasing means in its eiectiveposition during the entire return movement of the lifting frame from its raised position.

3. In apparatus of the character described, the combination of: a chassis comprising a supporting frame lhaving mounted thereon a set of wheels and a steering handle; a lifting frame mounted upon said chassisand adapted to be moved to and from a raised position where it engages and lifts a load;v means to elevate said lifting frame comprising, a hydraulic pump which is automatically operable as a holding means to hold said lifting frame in` its .elevated position until it is released, and means to detachably connect said steering handleand said hydraulic pump; releasing means to render said hydraulic pump ineffective as a holding means so that said lifting frame will be returned from its raised position; and means to automatically operate` said releasing means when said lifting frame approaches a permissible limit to thereby prevent excessiveraising of said lifting frame.

4. In apparatus of the character described, the

ing, a lever-linkage assembly, a foot treadle rockably mounted and operably connected so that when it is swung` downwardly movement is transmitted to said lever-linkage assembly, a treadle-'latching means to hold said treadle in depressed position, .and means to release said latch when the liftingframe has returned from its raised position. 'v

5. In apparatus of the character described, the combination of: a chassis comprising a supporting frame having mounted thereon a set of wheels and a steering handle; a lifting frame mounted upon`said chassis and adapted to be moved to and VAfrom a raised position where it engages and lifts a load; operating means to elevate said lifting frame and to hold said lifting frame in elevated position comprising, a hydraulic ram having a releasing rod which is operated to release the hydraulic ram and permitathe lifting frame to move from its raised position, and means to operate said hydraulic ram; releasing means to operate said releasing rod comprising, a vertically extending releasing lever pivoted at its lower end and having an arcuate side flange operably connected to said releasing rod, an Aelongated linkage 'means connected at one end to the-upper end of said releasing lever, a rockablev treadle connected to the other end of said elongated linkage means and mounted upon said supporting frame, a latching means toautomatically,hold said treadle in one extreme'position, said operating means including a spring which tends to hold said treadle in.l the other extreme position, and disengaging means associated'with said lifting frame to automatically disengage said latching means when the lifting frame has completely returned from its elevatedv position.

6. In apparatus of the character described, the

combination of: a chassis comprising a supporting frame having mounted thereon a set of wheels 4 and a steering handle; a lifting frame mounted upon said chassis and adapted to be moved to and from a raised position where it engages and lifts' a load; hydraulic lifting means to move said lift- -limit and to hold said releasing means effective until said lifting frame returns from said permissible limit.

'7. Inlift truck construction, the combination of a chassis including, a front axle structure, a

2,280,104 rear wheel structure, a plurality of supportingv wheels carried by said front and rearaxle structures, a yoke carrying said frontgwheel structure, a king bolt upon said yoke, a steering handle swingably mounted on said king bolt; a lifting frame mounted on said chassis to be moved upv ing its two arms slidably engaging opposite sides of said hydraulic ram and having its center portion mechanically engaged by said plunger, a pumping lever mechanically connectingsaid linkage means to said hydraulic ram so that mechanical power may be transmitted from said steering handle through said linkage means to operate said hydraulic ram, lifting means to member to said lifting frame, and safety means which is operated when said lifting frame approaches its maximum "desirable elevation which safety means prevents the operating means from raising said lifting frame beyond said maximum desirable elevation.

8. In lift truck apparatus, th'e combination of: a chassis construction; a lifting frame mounted upon said chassis to be moved upwardly to thereby lift the load; and a means to elevate said lifting frame including, a hydraulic ram carried by said chassis and having a lifting plunger and a pumping rod with the lifting plunger being adapted to move outwardly when .said pumping rod is operated, a lifting shaft mounted upon said chassis, a pumping lever rockably mounted upon the'central portion of said lifting shaft and having one arm mechanically connected to said pumping rod and another arm which may be connected to an actuating mechanism, and a pair of lifting arms mounted on said lifting shaft upon opposite sides of said lifting lever, said lifting arms being connected to said lifting frame and to exert forces on said shaft during each pumping stroke which forcesA are diametrically opposed to the forces then being exerted on said shaft by said lifting arm; v

10. In lift truck apparatus of the class described, the combination of: a base iframe;` a load-engaging means mounted upon said `base frame to be moved upwardly to thereby engage and lift the load; operating means to raisersaidk load-engaging means and automatically operable as a holding means to hold said load-engaging means in its raised position and including a rei leasing means which may be operated to permit the return of said load-engaging means from its raised position; and means which is moved to an operable position when said load-engaging means .approaches the permissible limit of its raising movement, said means being effective to operate said releasing means when said`load-engaging ymeans approaches said permissible limit and to hold said releasing means effective until said transmit the lifting movement from said U- load-engaging means retreats from sible limit.

1l. In lift truck apparatus of the class described, the combination of: a base frame; a load engaging and supporting structure mounted upon said baseframe and having load-engaging means to be moved upwardly to thereby engage and rlift the load, said structure including lifting arm means pivotally mounted'and adaptedl to swingto thereby impart the lifting force to said load-engaging meins; operating means to impart the lifting force to said lifting arm means to raise said load-engaging'means,`.said operating means being automatically operable as a holding means to hold said load-engaging means in its raised position and including a releasing means which may be operated to permit the reto said lifting, plunger and being adapted tov turn of said load-engaging means from its raised position; and safety means to limit the upward movement of said load-engaging means and operable when said load-engaging means approaches the permissible limit of its raising movement, said means comprising cooperating means upon said lifting-arm means and said releasing means which cooperate mechanically so `that the movement of said lifting arm means is effective to operate said releasing means when said load-engaging means approaches said permounted upon said chassis and connected thereto l by a plurality of substantially parallel link members which are moved from substantially horizontal position toward a vertical position to thereby raise said lifting frame, said link members including a lifting arm through which lifting Y movement of the lifting frame is transmitted; and operating means to transmit lifting movement to vsaid lifting arm^ comprising a Vhydraulic .ram mounted in a substantially horizontal position upon said cross-frame structure, a horizontally positioned transverse shaft carrying said lifting arm and providing a support for one end of said lifting frame, and a pumping arm mounted upon said shaft to transmit pumpingmovement to said hydraulic ram, said pumping arm being effective missible limit and so that said releasing means is thereafter held operative until said load-engaging means retreats from said permissible limit. 1

12. In lift truck apparatus of the class described, the combination of: a base frame; a load-engaging means mounted upon said base frame to be moved upwardly to thereby engage and lift the load; operating means to raise said load-engaging means and automatically operable as al holding means to hold said load-ensaging means in its raised position and including a releasing means 'which may be operated to permit the return of said load-engaging means from its raised position; manual means to. op-

moved to an operable position when said loademaille means reaches its 'lower position to thereby render said latching means ineffective.

said permis- 

